In a large skillet, heat oil over medium-high heat. Brown beef in batches. Transfer meat to a 3-qt. slow cooker. Stir in tomato sauce, water, chipotle peppers, adobo sauce, garlic, chili powder, cumin, bouillon, pepper and salt., Cook, covered, on low 6-8 hours or until meat is tender. If desired, serve with rice, flour tortillas, chopped tomatoes and shredded lettuce.